.middle > div:nth-child(1) {
    height: 50px;

}

.middle > div:nth-child(1) > div {
    border-bottom: 1px dashed gray;
}

.course-nav > div:hover .quan {
    visibility: visible;
}

.course-nav > div:hover {
    color: rgb(243, 101, 37);
    cursor: pointer;
}

.about-us .chinese-name {
    font-size: 50px;
    color: rgb(243, 101, 37);
    margin: 20px;
}

.about-us .english-name {
    font-size: 30px;
    margin: 20px;
}

.about-us > div:nth-child(2) img {
    margin: 0 20px 20px 0;
}

/*---------------------轮播carousel----------------------*/
.middle > div:nth-child(3) > div {
    overflow: hidden;
}

/*后代选择器*/
.carousel img {
    width: 200px;
    height: 200px;

}

.carousel > div {
    margin: 20px;
    text-align: center;
}

.carousel {
    /*css动画：动画名称  完成动画需要的时间  动画播放的次数*/
    animation: focus 5s infinite;
    /*animation-name: focus;*/
    /*animation-duration: 5s;*/
    /*animation-iteration-count: infinite;*/
}

@keyframes focus {
    0% {
        margin-left: 0;
    }
    /*20% {*/
    /*    margin-left: -100px;*/
    /*}*/
    /*40% {*/
    /*    margin-left: -350px;*/
    /*}*/
    50% {
        margin-left: -500px;
    }
    /*80% {*/
    /*    margin-left: -250px;*/
    /*}*/
    100% {
        margin-left: 0;
    }
}
